cregit-Linux how code gets into the kernel

Release 4.14 arch/x86/math-emu/fpu_emu.h

/* SPDX-License-Identifier: GPL-2.0 */
/*---------------------------------------------------------------------------+
 |  fpu_emu.h                                                                |
 |                                                                           |
 | Copyright (C) 1992,1993,1994,1997                                         |
 |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
 |                       Australia.  E-mail   billm@suburbia.net             |
 |                                                                           |
 +---------------------------------------------------------------------------*/

#ifndef _FPU_EMU_H_

#define _FPU_EMU_H_

/*
 * Define PECULIAR_486 to get a closer approximation to 80486 behaviour,
 * rather than behaviour which appears to be cleaner.
 * This is a matter of opinion: for all I know, the 80486 may simply
 * be complying with the IEEE spec. Maybe one day I'll get to see the
 * spec...
 */

#define PECULIAR_486

#ifdef __ASSEMBLY__
#include "fpu_asm.h"

#define	Const(x)	$##x
#else

#define	Const(x)	x
#endif


#define EXP_BIAS	Const(0)

#define EXP_OVER	Const(0x4000)	
/* smallest invalid large exponent */

#define	EXP_UNDER	Const(-0x3fff)	
/* largest invalid small exponent */

#define EXP_WAY_UNDER   Const(-0x6000)	
/* Below the smallest denormal, but
                                           still a 16 bit nr. */

#define EXP_Infinity    EXP_OVER

#define EXP_NaN         EXP_OVER


#define EXTENDED_Ebias Const(0x3fff)

#define EXTENDED_Emin (-0x3ffe)	
/* smallest valid exponent */


#define SIGN_POS	Const(0)

#define SIGN_NEG	Const(0x80)


#define SIGN_Positive	Const(0)

#define SIGN_Negative	Const(0x8000)

/* Keep the order TAG_Valid, TAG_Zero, TW_Denormal */
/* The following fold to 2 (Special) in the Tag Word */

#define TW_Denormal     Const(4)	
/* De-normal */

#define TW_Infinity	Const(5)	
/* + or - infinity */

#define	TW_NaN		Const(6)	
/* Not a Number */

#define	TW_Unsupported	Const(7)	
/* Not supported by an 80486 */


#define TAG_Valid	Const(0)	
/* valid */

#define TAG_Zero	Const(1)	
/* zero */

#define TAG_Special	Const(2)	
/* De-normal, + or - infinity,
                                           or Not a Number */

#define TAG_Empty	Const(3)	
/* empty */

#define TAG_Error	Const(0x80)	
/* probably need to abort */


#define LOADED_DATA	Const(10101)	
/* Special st() number to identify
                                           loaded data (not on stack). */

/* A few flags (must be >= 0x10). */

#define REV             0x10

#define DEST_RM         0x20

#define LOADED          0x40


#define FPU_Exception   Const(0x80000000)	
/* Added to tag returns. */

#ifndef __ASSEMBLY__

#include "fpu_system.h"

#include <uapi/asm/sigcontext.h>	/* for struct _fpstate */
#include <asm/math_emu.h>
#include <linux/linkage.h>

/*
#define RE_ENTRANT_CHECKING
 */

#ifdef RE_ENTRANT_CHECKING
extern u_char emulating;

#  define RE_ENTRANT_CHECK_OFF emulating = 0

#  define RE_ENTRANT_CHECK_ON emulating = 1
#else

#  define RE_ENTRANT_CHECK_OFF

#  define RE_ENTRANT_CHECK_ON
#endif /* RE_ENTRANT_CHECKING */


#define FWAIT_OPCODE 0x9b

#define OP_SIZE_PREFIX 0x66

#define ADDR_SIZE_PREFIX 0x67

#define PREFIX_CS 0x2e

#define PREFIX_DS 0x3e

#define PREFIX_ES 0x26

#define PREFIX_SS 0x36

#define PREFIX_FS 0x64

#define PREFIX_GS 0x65

#define PREFIX_REPE 0xf3

#define PREFIX_REPNE 0xf2

#define PREFIX_LOCK 0xf0

#define PREFIX_CS_ 1

#define PREFIX_DS_ 2

#define PREFIX_ES_ 3

#define PREFIX_FS_ 4

#define PREFIX_GS_ 5

#define PREFIX_SS_ 6

#define PREFIX_DEFAULT 7


struct address {
	
unsigned int offset;
	
unsigned int selector:16;
	
unsigned int opcode:11;
	
unsigned int empty:5;
};

struct fpu__reg {
	
unsigned sigl;
	
unsigned sigh;
	
short exp;
};


typedef void (*FUNC) (void);

typedef struct fpu__reg FPU_REG;

typedef void (*FUNC_ST0) (FPU_REG *st0_ptr, u_char st0_tag);
typedef struct {
	


u_char address_size, operand_size, segment;

} overrides;
/* This structure is 32 bits: */
typedef struct {
	
overrides override;
	
u_char default_mode;

} fpu_addr_modes;
/* PROTECTED has a restricted meaning in the emulator; it is used
   to signal that the emulator needs to do special things to ensure
   that protection is respected in a segmented model. */

#define PROTECTED 4

#define SIXTEEN   1		
/* We rely upon this being 1 (true) */

#define VM86      SIXTEEN

#define PM16      (SIXTEEN | PROTECTED)

#define SEG32     PROTECTED
extern u_char const data_sizes_16[32];


#define register_base ((u_char *) registers )

#define fpu_register(x)  ( * ((FPU_REG *)( register_base + 10 * (x & 7) )) )

#define	st(x)      ( * ((FPU_REG *)( register_base + 10 * ((top+x) & 7) )) )


#define	STACK_OVERFLOW	(FPU_stackoverflow(&st_new_ptr))

#define	NOT_EMPTY(i)	(!FPU_empty_i(i))


#define	NOT_EMPTY_ST0	(st0_tag ^ TAG_Empty)


#define poppop() { FPU_pop(); FPU_pop(); }

/* push() does not affect the tags */

#define push()	{ top--; }


#define signbyte(a) (((u_char *)(a))[9])

#define getsign(a) (signbyte(a) & 0x80)

#define setsign(a,b) { if ((b) != 0) signbyte(a) |= 0x80; else signbyte(a) &= 0x7f; }

#define copysign(a,b) { if (getsign(a)) signbyte(b) |= 0x80; \
                        else signbyte(b) &= 0x7f; }

#define changesign(a) { signbyte(a) ^= 0x80; }

#define setpositive(a) { signbyte(a) &= 0x7f; }

#define setnegative(a) { signbyte(a) |= 0x80; }

#define signpositive(a) ( (signbyte(a) & 0x80) == 0 )

#define signnegative(a) (signbyte(a) & 0x80)


static inline void reg_copy(FPU_REG const *x, FPU_REG *y) { *(short *)&(y->exp) = *(const short *)&(x->exp); *(long long *)&(y->sigl) = *(const long long *)&(x->sigl); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)68100.00%2100.00%
Total68100.00%2100.00%

#define exponent(x) (((*(short *)&((x)->exp)) & 0x7fff) - EXTENDED_Ebias) #define setexponentpos(x,y) { (*(short *)&((x)->exp)) = \ ((y) + EXTENDED_Ebias) & 0x7fff; } #define exponent16(x) (*(short *)&((x)->exp)) #define setexponent16(x,y) { (*(short *)&((x)->exp)) = (y); } #define addexponent(x,y) { (*(short *)&((x)->exp)) += (y); } #define stdexp(x) { (*(short *)&((x)->exp)) += EXTENDED_Ebias; } #define isdenormal(ptr) (exponent(ptr) == EXP_BIAS+EXP_UNDER) #define significand(x) ( ((unsigned long long *)&((x)->sigl))[0] ) /*----- Prototypes for functions written in assembler -----*/ /* extern void reg_move(FPU_REG *a, FPU_REG *b); */ asmlinkage int FPU_normalize(FPU_REG *x); asmlinkage int FPU_normalize_nuo(FPU_REG *x); asmlinkage int FPU_u_sub(FPU_REG const *arg1, FPU_REG const *arg2, FPU_REG * answ, unsigned int control_w, u_char sign, int expa, int expb); asmlinkage int FPU_u_mul(FPU_REG const *arg1, FPU_REG const *arg2, FPU_REG * answ, unsigned int control_w, u_char sign, int expon); asmlinkage int FPU_u_div(FPU_REG const *arg1, FPU_REG const *arg2, FPU_REG * answ, unsigned int control_w, u_char sign); asmlinkage int FPU_u_add(FPU_REG const *arg1, FPU_REG const *arg2, FPU_REG * answ, unsigned int control_w, u_char sign, int expa, int expb); asmlinkage int wm_sqrt(FPU_REG *n, int dummy1, int dummy2, unsigned int control_w, u_char sign); asmlinkage unsigned FPU_shrx(void *l, unsigned x); asmlinkage unsigned FPU_shrxs(void *v, unsigned x); asmlinkage unsigned long FPU_div_small(unsigned long long *x, unsigned long y); asmlinkage int FPU_round(FPU_REG *arg, unsigned int extent, int dummy, unsigned int control_w, u_char sign); #ifndef MAKING_PROTO #include "fpu_proto.h" #endif #endif /* __ASSEMBLY__ */ #endif /* _FPU_EMU_H_ */

Overall Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)87098.53%1875.00%
Randy Dunlap50.57%14.17%
Linus Torvalds30.34%14.17%
Ingo Molnar30.34%28.33%
Arnd Bergmann10.11%14.17%
Greg Kroah-Hartman10.11%14.17%
Total883100.00%24100.00%
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